Variable frequency dewatering assembly

ABSTRACT

A variable frequency foil (VFF) box assembly and mechanisms for moving individual foils/foil beams and individual foil beam sets relative to each other to adjust the frequency of a paper making machine, and method of use are provided. The VFF box assembly allows for continuously and uniformly adjusting the pitch distances of individual foils within foil sets over a finite range, and also adjusting the distance between foil sets during the continuous operation of a paper making machine. Also provided is a variable frequency assembly comprising a combination of dewatering elements such as one or more foil elements and table rolls, a multi-surfaced foil element, and/or an adjustable angle foil element.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/972,144 (Publ. No. US2002/0067544), filed Oct.5, 2001, now U.S. Pat. No. ______, and claims the benefit of U.S.Provisional Application Serial No. 60/238,930, filed Oct. 10, 2000.

FIELD OF THE INVENTION

[0002] The present invention relates to an apparatus and system foraltering the frequency of a Fourdrinier table in the formation of acontinuous web of paper or other material.

BACKGROUND OF THE INVENTION

[0003] In the manufacture of paper, a stock of fibers and mineralfillers suspended in water, is deposited onto the moving wire on theFourdrinier table of a paper machine. An example of a conventionalFourdrinier table assembly 10 is shown in FIG. 1. The table 10 includesa head box 12 from which a stock suspension is deposited onto acontinuously moving wire 14, a breast roll 16, forming unit 18, and aseries of gravity foil boxes 20 and vacuum foil boxes 22, a dandy roll24, a series of suction boxes 26, and a couch roll 28. As the stocksuspension moves along the wire 14 and over the foil boxes 20, 22 andsuction boxes 26, the water is removed to form a continuous web.

[0004] Many theories have been applied to enhance water removal andachieve proper fiber orientation and distribution to form the fibersheet, but with varying degrees of success. In one practice, table rollshave been used to apply a vacuum pulse by drawing water from theundersurface of the wire, and then create a pressure pulse by pushingwater through the fabric to agitate the stock suspension for properfiber orientation. However, as production speeds increased and highervacuum forces were applied, excessive jumping of the stock of theforming sheet occurred which adversely affected formation quality. Withthe development of hydrofoils, control of water removal and formationimproved.

[0005] From 1960 to 1970, machines became faster and wider, and thegravity foil box was introduced. The device consisted of a bridge-likeframework that spanned the table with “T” bars installed for theindividual blades. Foil blades could be removed or added on the run, andthe spacing of the “foil banks” was random at best. The concept of foilangle was then proposed and experimentation was performed to determineoptimal foil blade angle and foil bank spacing on the machine, which areimportant to drainage and formation.

[0006] A subsequent development was the concept of table harmonics, anengineering principle stating that the energy contained within the stockat the exit of the head box can be amplified (for improved drainage andformation) by the spacing of the foils. The harmonic excitation of thestock can be further altered by placing foil banks at specific intervalsalong the table based on the tip-to-tip spacing of the foils within eachbank. This principle gave rise to the practice of placing the start of afirst foil bank in the vicinity of three to six feet from the exit ofthe head box. It was also learned that the ability to add or removefoils from a bank significantly impacted sheet properties. However, foilbanks could not be moved while the machine was running due to thetremendous drag imparted onto the foils. In about 1978, the concept oftable frequency was combined with table harmonics to maximize drainageand formation. It was discovered that packing a table with foils spacedan appropriate distance apart, and then removing the foils from thetable in strategic locations, achieved the desired Fourdrinier frequencywhen operating at higher speeds, up to 3300 fpm and higher.

[0007] Another development included the introduction of an automatedfoil bank that varied the pitch of the foil blade (the variable anglefoil) to impact drainage and formation. It was also determined that thebest formation and drainage for any given table was a frequency between55 Hz and 105 Hz. In addition, a foil bank system was introduced thatcould raise foils into the wire and/or drop them from contact with thewire, but only allowed the use of a finite number of frequencies (i.e.,either 55 or 75 Hz) by the papermaker. This limits the success of thepapermaker where another frequency (i.e., 61 Hz) would be optimal forformation and drainage.

[0008] The function of the Fourdrinier table is two-fold: (1) tode-water the stock utilizing the effects of both gravity and appliedvacuum, and (2) to subject the stock to periodic excitation as the wirepasses over a series of inverted continuous hydrofoil blades (foils)that extend transversely across the table in a cross machine direction,i.e., at a right angle to the direction in which the wire travels.

[0009] Traditionally, a Fourdrinier table include several sections offoil groupings, or sets, of approximately six foils each, that aremounted on individual foil support beam structures (i.e., T-bar mounts)spaced along the length of the table at set intervals to create adesired pulse frequency. The foil sets are normally affixed to asub-structure of the table commonly referred to as a “box.” An exampleof a conventional foil box 30 having four foils 34 is shown in FIG. 2.The direction of the movement of the wire (not shown) over the foils 34is shown by arrow 30. The boxes are further sub-classified into eithergravity boxes 20 or vacuum boxes 22 (FIG. 1). The first several foilsets aid in de-watering the stock under the influence of gravity.Further down the table as the water content of the stock decreases, avacuum is applied from beneath the wire to facilitate the de-wateringprocess.

[0010] The foils aid in the de-watering process and also impart apressure impulse to the stock suspension. The impulses serve to keep thefibers and fillers in suspension during the de-watering process yieldinga paper stock of uniform consistency. A single pulse is not adequate tocontrol the stock on the Fourdrinier table. Rather, a series of pulsesis generated and repeated at a standard interval.

[0011] The frequency of these impulses is referred to as the Fourdrinierfrequency, which is defined as the velocity of the wire (ininches-per-second) divided by the pitch distance between the foils (ininches). It is well known to those versed in the art/science ofpapermaking that the frequency of these impulses has a dramatic effectupon the formation of the paper fibers. Under most circumstances,acceptable formation occurs at a Fourdrinier frequency between about 55hertz and about 90 hertz. However, the current state of the art/scienceof paper formation relies upon the strategic use of conventional foilblades, multi-pulse foils, and/or foil boards that compromise effectivestock de-watering with appropriate stock excitation frequencies.

SUMMARY OF THE INVENTION

[0012] The present invention provides variable frequency foil (VFF) boxassemblies and mechanisms for moving individual foils/foil beams andindividual foil beam sets relative to each other to adjust the frequencyof a paper making machine independent of the wire speed. The inventionallows for continuously and uniformly adjusting the pitch distances ofindividual foils within foil sets over a finite range, and alsoadjusting the distance between foil sets during the operation of a papermaking machine. The invention also provides variable frequencydewatering assemblies that comprise various dewatering elements such asa foil beam and table roll in combination, and assemblies thatincorporate multi-surface foil elements and adjustable angle foilblades.

[0013] In one aspect, the invention provides a foil beam assembly. Inone embodiment, the foil beam assembly comprises at least a first and asecond foil beam set, each foil beam set comprising a leading foil beam,a trailing foil beam, and at least one intermediate foil beam disposedtherebetween, and a mechanism to laterally move the foil beams and thefoil sets relative to each other. The mechanism is connected to each ofthe foil beams and to the first and second foil beam set. The mechanismis operable to laterally move the foil beams to alter the pitch distancesuch that each of the foil beams are spaced apart by a standardinterval, and to laterally move at least one of the foil beam sets toalter the distance therebetween such that the foil beam sets are spacedapart by an integer multiple of the standard interval.

[0014] In one embodiment of the foil beam assembly, the mechanism cancomprise a mating screw and nut assembly affixed to a first foil beamand an adjacent second foil beam, and in rotatable contact with a gearmounted on a shaft, whereby rotating the shaft causes lateral movementof at least the second foil beam to alter the pitch distance between thefirst and second foil beams. In another embodiment, the mechanism of thefoil beam assembly comprises a hydraulic or pneumatic device mounted onthe first and second foil beams and operable to laterally move at leastthe second foil beam relative to the first foil beam. In anotherembodiment of the foil beam assembly, the mechanism can comprise anactivating screw and nut assembly affixed to the second foil beam andoriented perpendicular to the foil beams, the activating screw connectedto an actuating device operable to move the activating screw tolaterally move the second foil beam relative to the first foil beam. Inyet another embodiment, the mechanism of the foil beam assembly cancomprise nut members mounted on a surface of the first and second foilbeams, and activating screw members engaged through the nut members andextending perpendicular to the foil beams, the activating screw membersconnected to actuators comprising a worm/gear assembly mounted on adrive shaft, wherein movement of the actuators move the activating screwmembers which laterally move at least the second foil beam relative tothe first foil beam. Yet another embodiment of a mechanism for use inthe foil beam assembly comprises a pantograph assembly connected to thefirst and second foil beams, wherein extension and retraction of thepantograph moves at least the second foil beam relative to the firstfoil beam to alter the pitch distance therebetween. A further embodimentof the mechanism of the foil beam assembly comprises a telescoping shaftassembly.

[0015] In another aspect, the invention provides a method of varying thefrequency of a foil beam set. In one embodiment, the method comprisesthe steps of providing at least a first and second foil beam set, eachset comprising two or more foil beams mounted on a support structure,and a mechanism interconnecting the foil beams and the foil beam sets,the mechanism structured to laterally move the foil beams relative toeach other and to laterally move the foil beam sets relative to eachother; and actuating the mechanism to laterally move the foil beams toalter the distance therebetween and maintain the foil beams at adistance X relative to each other, and to laterally move the foil beamsets relative to each other to a distance as an integer multiple of thedistance X, wherein the combined frequency of the foil beam sets ismaintained at about 50 to about 90 hertz.

[0016] In another aspect, the invention provides an assembly fordewatering a suspension in a papermaking apparatus. In one embodiment,the assembly comprises first and second sets of dewatering elementsmounted on a support structure, at least one set including at least onefoil element and at least one table roll, and an actuating mechanisminterconnecting the dewatering elements and the sets and operable tolaterally move and space apart the dewatering elements by a standardinterval, and to laterally move at least one of the sets to space apartthe sets by an integer multiple of the standard interval. In a method ofvarying the frequency of a set of dewatering elements, the actuatingmechanism is activated to laterally move the dewatering elementsrelative to each other to a distance X and to laterally move the setsrelative to each other to a distance as an integer multiple of thedistance X.

[0017] In another embodiment of a foil assembly according to theinvention, the assembly comprises at least one multi-surfaced foilelement. In one embodiment, the multi-surfaced foil element comprises aunitary structure having two wire-contacting surfaces spaced apart bythe standard interval X with a suction-forming section and a drainagesection therebetween. Such a foil element is useful to achieve a pitchdistance between wire contact surfaces of about 1 inch to up to 2½inches, although higher pitch distances can be used if desired. In anembodiment of a VF assembly, the assembly can comprise a multi-surfacedfoil element in combination with a foil having a single wire contactingsurface or other foil element, and/or a table roll or other dewateringelement.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Preferred embodiments of the invention are described below withreference to the following accompanying drawings, which are forillustrative purposes only. Throughout the following views, thereference numerals will be used in the drawings, and the same referencenumerals will be used throughout the several views and in thedescription to indicate same or like parts.

[0019]FIG. 1 is an illustration of a conventional Fourdrinier tableassembly.

[0020]FIG. 2 is a perspective view of a conventional foil box havingfour foils.

[0021]FIG. 3 is a schematic top plan view of an embodiment of anassembly of variable frequency foil boxes according to the inventioncomprising a series of three foil sets (boxes), each foil set having sixfoils.

[0022]FIG. 4 is a schematic top plan view of the variable frequency foilbox assembly of FIG. 3, showing foils having been removed from two foilsets.

[0023]FIG. 5 is a perspective, partial view of embodiment of a variablefrequency foil box according to the invention utilizing a double actingscrew mechanism to move the foil support beams.

[0024]FIG. 6 is a perspective view of another embodiment of a variablefrequency foil box according to the invention utilizing a foil boxarrangement using a hydraulic/pneumatic cylinder mechanism to move thefoil support beams.

[0025]FIG. 7 is a perspective view of another embodiment of a variablefrequency foil box according to the invention utilizing a multiple leadscrew mechanism to move the foil support beams.

[0026] FIGS. 8A-8C are illustrations of another embodiment of a variablefrequency foil box according to the invention utilizing pantographassemblies to move the foil support beams. FIG. 5A is a top perspectiveview of the variable frequency foil box. FIG. 8B is a bottom plan viewof the variable frequency box of FIG. 8A, taken along lines A-A, andshowing the attachment of the foil support beams to the center points ofthe underlying pantograph assembly. FIG. 8C is a side elevational viewof the variable frequency box of FIG. 8B, taken along lines B-B.

[0027] FIGS. 9A-9B are top and bottom perspective views, respectively,of another embodiment of a variable frequency foil (VFF) box accordingto the invention assembled with a second set of foils, showing theleading and trailing foil beams of each set mounted on linear rails, andutilizing pantograph assemblies, right-angle gearboxes and lead screwassemblies to move the foil support beams.

[0028]FIG. 10 is another embodiment of a variable frequency foil box ofthe invention illustrating a rack and pinion gearing mechanism that canbe utilized to establish and maintain equidistant spacing betweenadjacent foil beams.

[0029]FIG. 11 is a perspective view of an embodiment of a variablefrequency dewatering assembly according to the invention comprisingdewatering elements in the form of foil beams and a table roll mountedon linear rails.

[0030]FIG. 12 is a perspective view of an embodiment of a table roll asused in the assembly in FIG. 11.

[0031]FIG. 13 is a partial side elevational view of the table roll ofFIG. 12

[0032]FIG. 14 is an end view of the table roll of FIG. 13, taken alongline 14-14.

[0033]FIG. 15 is a cross-sectional view of the table roll of FIG. 13,taken along line 15-15.

[0034]FIG. 16 is a partial perspective view of an embodiment of amulti-surfaced foil element according to the invention.

[0035]FIG. 17 is a cross-sectional view of the foil element of FIG. 16taken along line 17-17, showing a moving wire in contact with thesurfaces of the foil element.

[0036]FIG. 18 is cross-sectional view of two multi-surfaced foilelements placed in an assembly.

[0037]FIG. 19 is a sectional view of an embodiment of a prior artadjustable angle foil.

DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention relates to mechanisms and methods forvarying the frequency of a Fourdrinier table, independent of the wirespeed, by continuously and uniformly adjusting the pitch distances ofindividual foils within foil sets over a finite range, and alsoadjusting the distance between foil sets (boxes). The mechanisms of theinvention can be used in gravity box sections of the infeed end of apaper machine Fourdrinier table, among other applications. The inventionwill be described generally with reference to the drawings for thepurpose of illustrating the present preferred embodiments only and notfor purposes of limiting the same.

[0039] An assembly 37′ comprising three variable frequency foil (VFF)boxes (“foil sets”) 36 a′, 36 b′, 36 c′ for use in a Fourdrinier table,is illustrated in FIG. 3. As typical, each VFF foil set 36 a′-36 c′incorporates up to six foils 38′ (38′a-c, 1-6) affixed to individualfoil support beam structures 40′ (40′a-c, 1-6), although an individualfoil set can comprise more or less foils as desired. The width 42′ ofthe foil boxes 36 a′-36 c′ corresponds to the width of the paper makingmachine. The foil support beams 40′ are mounted so as to preventmovement along their respective centerlines 44′, and to provide freemovement along an axis perpendicular to their respective centerlines.

[0040] Utilizing a mechanism according to the invention, the frequencyof an individual foil box or set 36 a′-36 c′ (“box frequency”) isinfinitely adjustable over a finite range by altering the pitch distancebetween the foil blades 38′ within a foil set such that all the foilsremain substantially equally spaced at a distance “X” throughout theadjustment range. According to the invention, in addition to maintaininga spacing of “X” between the foils/foil beams within a single foil set36 a′-36 c′ the relative distance between adjacent foil sets is alsomaintained at a standard interval (e.g., the foil spacing distance “X”)or an integer multiple of that standard interval to sustain the desiredfrequency of the Fourdrinier table as a whole (“table frequency” or“Fourdrinier frequency”). For example, referring to foil sets 36 a′ and36 b′, if the standard interval between foil support beams 40 a 1′-40 a6′ is X-inch (e.g., 5¼-inch), then the distance between the last(trailing) foil beam 40 a 6′ on the first foil set 36 a′ and the leadingfoil beam 40 b 1′ on the next (second) foil set 36 b′ would be either1X, 2X, 3X-inch, etc. (5¼, 10½, 15¾-inch, etc.), and the distancebetween the last (trailing) foil beam 40 a 6′ on the second foil set 36a′ to the leading foil beam 40 c 1′ on the next (third) foil set 36 c′would also be either 1X, 2X, 3X-inch etc. (5¼, 10½, 15¼-inch, etc.), andso forth. This is accomplished by altering the distances betweenadjacent foil sets (36 a′ to 36 b′, 36 b′ to 36 c′) utilizing amechanism according to the invention. As depicted in FIG. 3, thestandard interval between foils is “X”, and the distance between foilsets is “2X”.

[0041] In addition, one or more of the foil support beams 40′ within afoil set can be removed to effect desirable changes to the rate at whichwater is drained from the stock. For example, as depicted in FIG. 4, thefourth foil beam 40 a 4′ has been removed from the first foil set 36 a′,and foil beams 40 b 4′ and 40 c 2′ have been removed from the second andthird foil sets 36 b′, 36 c′, respectively. Removal of foil beamspreferably does not alter the Fourdrinier frequency once established.Removal of every other foil beam in a foil set results in a 2X spacingbetween foil beams and a frequency that is one-half of that achievablewith a foil set in which all six foil beams 40′ are provided at aspacing of “X”.

[0042] The table frequency or Fourdrinier frequency is altered as afunction of wire speed and foil pitch distance according to thefollowing formula:$\frac{{Velocity}\quad {of}\quad {the}\quad {wire}\quad \left( {{inch}\text{/}{second}} \right)}{{Pitch}\quad {distance}\quad {between}\quad {foils}\quad ({inches})}$

[0043] Table 1 shows the Fourdrinier frequencies over a range of wirespeeds and foil pitch distances, which is preferably about 50 hertz toabout 90 hertz.

[0044] One embodiment of an actuating mechanism 45(1)′ utilized in avariable frequency foil box (set) according to the invention to alterthe frequency of a Fourdrinier table is depicted in FIG. 5, illustratedas VFF box (set) 36 a′ for explanation purposes. The actuating mechanism45(1)′ of the VFF set 36 a′ comprises a series combination ofdouble-lead acme type screws 46′ engaged with a single rotatable carrieror device shaft 48′ via spur gears 60′, 62′, which utilizes a commonactuating means (not shown), such as an electric motor, an air motor andvalving system, or other mechanism known and used in the art. Theactuating mechanism 45(1)′ is operable to provide equidistant spacing ofthe foil support beams 40′, and adjacent foil sets (36′) (not shown) onthe Fourdrinier table. The shaft 48′ is oriented perpendicular to thefoil support beams. A male threaded lead screw 46′ is affixed to thetrailing side 50′ of each foil support beam 40 a 1′, 40 a 2′. A “doublethreaded” rotating nut 52′ with a mating female thread on the innersurface (not shown) is engaged onto the male threaded lead screw 46′.The outside diameter of the nut 52′ is machined with an opposite handthread (outer thread) 54′ of identical pitch as the male threaded leadscrew 46′. The outer thread 54′ of the rotatable nut 52′ is engaged withthe inner threads (not shown) of a mating (fixed) nut 56′ affixed to theleading side 58′ of the following (trailing) foil support beam 40 a 2′.A gear 60′ affixed to the face of the rotatable nut 52′ meshes with asecond gear 62″ affixed to a rotatable carrier shaft 48′.

[0045] Rotating the carrier shaft 48′ turns the double threadedrotatable nut 52′. As the double threaded nut 52′ turns in onedirection, it further engages the lead screw 46′ on the leading foilsupport beam 40 a 1′ while being further engaged into the mating (fixed)nut 56′ mounted on the trailing foil support beam 40 a 2′. As thecarrier shaft 48′ rotates in the opposite direction, the processreverses. The carrier shaft 48′ has additional gears affixed to it (notshown) that simultaneously actuate an identical mechanism for thesubsequent foil support beams 40 a 3′, 40 a 4′, 40 a 5′ (not shown).With the first (leading) foil beam 40 a 1′, 40 b 1′, 40 c 1′ of eachfoil set 41 a′-41 c′ affixed to the box, and each subsequent foil beamconnected to the preceding foil beam via the aforementioned mechanism,equidistant spacing of the intermediate and trailing foil beams ismaintained throughout the range of adjustment. The actuating mechanism45(1)′ is preferably located at or near the ends 63′ of the foil supportbeams 40′. Additional mechanisms 45(1) can be equally spaced between theends on boxes of greater width.

[0046] Another embodiment of a variable frequency foil (VFF) box of theinvention is depicted in FIG. 6, illustrated as VFF box 36 a′. As shown,VFF box 36 a′ comprises five foils 38 a 1′-38 a 5′, each mounted on afoil support beam 40 a 1′-40 a 5′. As further depicted, the variablefrequency foil box 36 a′ utilizes an actuating mechanism 45(2)′comprising a series combination of hydraulic or pneumatic cylinders 64′with integral position feedback transducers 66′, utilizing anelectronically-controlled system of actuating valves (not shown). Theactuating mechanism 45(2)′ is utilized to accomplish the equidistantspacing of foils 38 a 1′-38 a 5′ and adjacent foil sets (not shown) bylateral movement. In the illustrated embodiment, at least two hydraulicor pneumatic cylinders 64′ are attached to each foil support beam 40 a1′-40 a 5′ with the ends of the cylinders (rod-ends), affixed to theupstream (leading) side 58′ of the foil beam or the downstream(trailing) side 50′ of the foil beam (as shown). The individual foilbeams 40 a 1′-40 a 5′ are preferably supported by at least two linearbearings 68′ (i.e., linear pillow blocks) that are supported by shafts70′ oriented perpendicular to the foil support beams 40 a 1′-40 a 5′ toinsure the lateral alignment of the beams in the machine such that thesupport beams are held down and do not move in either lateral orvertical directions.

[0047] An electronic control system utilizing a programmable logiccontroller (PLC) (not shown) can be used to actuate the cylinder valves64′ to effect changes in the relative position of adjacent foil supportbeams 40 a 1-40 a 5′. The cylinders 64′ preferably comprise positiontransducers 66′ that provide a feedback signal to the PLC to indicateposition changes. Further “tuning” of the foil positions can be effectedby the PLC to position the foil beams 40 a 1′-40 a 5′ and foils 38 a1′-38 a 5′ in the precise location(s) required to achieve the desiredbox frequency.

[0048] Another embodiment of a variable frequency foil box according tothe invention is depicted in FIG. 7, illustrated as VFF box 36 a′ fordiscussion purposes. As shown, the variable frequency foil box 36 a′utilizes an actuating mechanism 45(3)′ comprising a series of actuating(lead) screw (ball screw) assemblies 72′, along with a common actuator73′, which are utilized to accomplish the equidistant spacing of foils38 a 1′-38 a 5′ and adjacent foil sets (not shown). In this embodiment,each foil support beam 40 a 1′-40 a 5′ incorporates a nut 76′ into whichan actuating (lead) screw 74′ is engaged, the axis of the actuatingscrew being perpendicular to that of the foil support beams 40 a 1′-40 a5′. Preferably, each foil beam 40 a 1′-40 a 5′ comprises at least twonut/actuating screw assemblies positioned along the length of the foilbeam. The actuating screw 74′ extends forward (or backward) to a pointbeyond the leading foil beam 40 a 1′ (or trailing foil beam 40 a 2′-40 a5′). The actuating means (actuator) 73′ for each actuating screwassembly 72′ comprises a worm gear assembly (or worm and pinionassembly) 78 a′-78 d′ whereby the gear 80′ is affixed to the actuatingscrew 74′ and the engaging worms 82′ are coupled in parallel by a commondrive shaft 84′ that is connected to an actuating device 85′ such as adrive motor, a hydraulic or pneumatic pump, an air compressor and valvesystem, or other like mechanism known and used in the art for turning adrive shaft. The worm gear ratios increase incrementally from oneactuating screw to the next actuating screw, for example, a ratio ofabout 10:1 for worm gear assembly 78 a′, an about 10:2 ratio forassembly 78 b′, an about 10:3 ratio for assembly 78 c′, an about 10:4ratio for assembly 78 d′, and so forth, whereby ten (10) revolutions ofthe worm 82′ yields one (1) (or 2, 3, 4, etc.) revolution of the gear80′ to insure the equidistant spacing of each foil beam 40 a 1′-40 a 5′throughout their respective ranges of motion. Referring to theembodiment shown in FIG. 6, the individual foil beams 40 a 1′-40 a 5′are preferably supported by at least two linear bearings (i.e., linearpillow blocks) 68′ that are supported by shafts 70′ orientedperpendicular to the foil beams 40 a 1′-40 a 5′ to insure the lateralalignment of the beams in the machine such that the beams are held downand do not move in either lateral or vertical directions. The linearbearings (68′) can be designed and sized such that the actuating leadscrews 74′ pass through the linear bearings (68′) without engaging screwthreads, in order to provide additional support to the actuating screws74′. With this embodiment, the number of parts (i.e., part count) thatcomprise the assembly 45(3)′ and subsequent alignment requirements aregreatly simplified.

[0049] As shown in FIGS. 8A-8C, in-another embodiment of a variablefrequency foil box, illustrated as VFF set 36 a′, at least twopantograph assemblies 88′ are utilized as a mechanism 45(4)′ along witha common actuating means (actuator) (not shown) to accomplish theequidistant spacing of the foil beams 40 a 1′-40 a 5′, and adjacent foilsets (not shown). Referring to FIG. 8B, each foil beam 40 a 1′-40 a 5′is attached to a center pivot 86′ of the pantograph assembly 88′ which,by design, insures that the spacing between the foil support beams 40 a1′-40 a 5′ remains substantially equidistant throughout the range ofmotion. The pantograph assembly 88′ comprises links 90′ that are securedwith a fastener 92′ at the pivot point of the links, including thecenter pivots 86′ of the pantograph assembly. In operation, thepantograph assembly 88′ accordions or extends (expands) outward (arrow94′) and retracts inward (arrow 96′), which draws at least theintermediate foil beams 40 a 2′-40 a 4′ along and into position. Theposition of the trailing blade 38 a 5′ can be adjusted by use of atleast two linear actuating (lead) screw assemblies 72′ connected inparallel by a common drive shaft 84′, and attached to both the leadingfoil beam 40 a 1′ and the trailing foil beam 40 a 5′. As the actuatingscrew assembly 72′ moves the trailing foil beam 40 a 5′, the pantographassembly 88′ draws the intermediate foil beams 40 a 2′-40 a 4′, whichare moved proportionally with the trailing foil beam 40 a 5′. Theindividual foil beams 40 a 1′-40 a 5′ are preferably supported by atleast two linear bearings 68′ (i.e., linear pillow blocks) supported byshafts 70′ oriented perpendicular to the foil support beams 40 a 1′-40 a5′ to insure the lateral alignment of the beams in the machine and tocontrol lateral and vertical movement.

[0050] Another embodiment of a variable frequency foil box according tothe invention, illustrated as VFF sets 36 a′, 36 b′, is depicted inFIGS. 9A-9B. As shown, a linear rail system 98′ for supporting the foilbeams can be used in place of a conventional “box” type structure (e.g.,FIG. 6). The linear rail system 98′ can be affixed to the frame 100′ ofa Fourdrinier table 10′ (shown in phantom). Preferably, as shown, therail system 98′ comprises two parallel rails, pairs of rails, an innerrail pair 99 a′ and an outer rail pair 99 b′. The foil beams can bemounted on the rail pairs 99 a′, 99 b′ by means of linear bearings 101a′, 101 b′. The foil beams are preferably mounted on the rails 99 a′, 99b′ in an offset or alternating manner, such that one bearing 101 a′ (andbeam) is mounted on the inner rail pair 99 a′ and the adjacent orfollowing bearing 101 b′ (and beam) is mounted on the outer rail pair 99b′. By offsetting or alternating the placement of the linear bearings101 a′, 101 b′ of adjacent foil beams on the inner and outer rail pairs99 a′, 99 b′, the beams can be moved relatively close together.Additionally, in this configuration, the distance that the leadingsupport beam 40 b 1′ of the second (trailing) foil beam set 36 b′ cantravel forward is increased, thus yielding application over a broaderrange of machine speeds and table frequencies than with a conventionalbox-type structure where the end of the box limits how far the leadingfoil beam 40 b 1′ can travel forward.

[0051] As shown in FIG. 9B, the two foil beam sets 36 a′, 36 b′,totaling ten (10) beams are illustrated as being interconnectedutilizing an actuating mechanism 45(5)′ comprising a telescopingassembly (122′) and pantograph assemblies 88′, although another of theactuating mechanisms and methods described herein can be utilized toaccomplish equidistant spacing of the foils beams 40 a 1′-40 a 5′, 40 b1′-40 b 5′, and the foil beam sets 36 a′, 36 b′.

[0052] As illustrated, each of the foil beam sets 36 a′, 36 b′, comprisea leading foil beam 40 a 1′, 40 b 1′, three trailing intermediate foilbeams 40 a 2′-40 a 4′, 40 b 2′-40 b 4′, and a trailing end foil beam 40a 5′, 40 b 5′. In the first foil beam set 36 a′, the leading foilsupport beam 40 a 1′ is affixed on the rail by a mounting (bracket)device 102′. An actuating mechanism 45(1)′-45(5)′ according to theinvention, and also subsequently described mechanism 45(6)′, can be usedto move and space apart the intermediate foil support beams 40 a 2′-40 a4′, and the trailing support beam 40 a 5′ of the first beam set 36 a′ ata distance X relative to the leading support beam 40 a 1′. In the secondfoil beam set 36 b′, the leading support beam 40 b 1′ is not affixed tothe rail and is slideable along the rail. The actuating mechanism of theinvention that is utilized, functions to move the (second) leadingsupport beam 40 b 1′ at an integer multiple of X distance (1X, 2X, 3X,etc.) relative to the preceding trailing support beam 40 a 5′ of thefirst foil beam set 36 a′. The intermediate foil support beam 40 b 2′-40b 4′, and the trailing support beams 40 b 5′ of the second foil beam set41 b′ are moved and spaced apart at a distance X relative to the(second) leading support beam 40 b 1′.

[0053] Referring again to FIG. 9B, at least two right-angle gearboxes104′ (illustrated as four gear boxes) are attached to the leading foilsupport beam 40 a 1′, 40 b 1′ of each foil set 36 a′, 36 b′. Thegearboxes 104′ are connected to each other via connecting shafts 106′ toprovide uniform rotary motion of the output shafts 108′. Connected toeach gearbox 104′ is a lead screw 110′, preferably having 6 threads perinch (6-pitch screw). Each lead screw 110′ is engaged into a mating nut112′, which is in turn attached to the trailing support beam 40 a 5′, 40b 5′ via a mounting (bracket) assembly 114′ that anchors the mating nut112′ and prevents rotation. An additional right-angle (outboard) gearbox116 a′, 116 b′ is mounted near the end of each of the leading supportbeams 40 a 1 ′, 40 b 1 ′. The outboard gearbox 116 a′, 116 b′ isconnected to the adjacent gearbox 104′ via a connecting (output) shaft120 a′.

[0054] The output shaft 124′ of the outboard gearbox 116 a′ is connectedto a telescoping spline shaft assembly 122′, which is in turn attachedto the input shaft (not shown) of the outboard gearbox 116 b attached tothe (second) leading support beam 40 b 1′. This assembly connects thetwo foil sets 36 a, 36 b′ together. The outboard gearbox 116 b′ on the(second) leading support beam 40 b 1′ is connected via connecting outputshaft 120 b′ to the adjacent gearbox 104′, by shafts 106′ to theremaining gearboxes 104′, and by output shaft 120 b″ to another outboardgearbox 116 b″ mounted at the opposite end of the leading support beam40 b 1′, to control the foils of the second foil set 36 b′.

[0055] The secondary output shafts (not shown) of the outboard gearboxes 116 b′, 116 b″, are coupled to screws 130′, preferably having 4threads per inch (4-pitch screws). The screws 130′ are engaged intomating nuts 132′ that are mounted to the rigid machine frame 100′ viamounting brackets 134′.

[0056] To adjust the foil box assembly, the input shaft 136′ on theoutboard gearbox 116 a′ of the (first) leading support beam 40 a 1′ isrotated. This, in turn, rotates all of the gearbox output shafts (andconnected screws and shafts) at a 1:1 ratio.

[0057] As the assembly in FIGS. 9A-9B is illustrated as having five (5)foils per foil set 36 a′, 36 b′, there exists four (4) interfoil spacesat a distance (X). The interset space between the first foil set 36 a′and the second foil set 36 b′ is twice (2X) the standard distance (X)between adjacent foils within each of the sets. During adjustment of thefrequency of the table, it is preferred that the (first) leading foilsupport beam 40 a 1′ of the first foil set 41 a′ is moved 1.5 times(1.5X) the distance that the trailing support beam 40 a 5′ of the firstfoil set 41 a′ is moved. To insure this relationship, it is preferredthat a 6-pitch screw is used within the foil sets 41 a′, 41 b′, and a4-pitch screw is used between the foil sets 41 a′, 41 b′.

[0058] As shown in FIG. 10, in yet another embodiment of a variablefrequency foil box according to the invention, illustrated as foil set36 a′, opposing rack and pinion gear sets are utilized as an actuatingmechanism 45(6)′ to accomplish equidistant spacing of foil support beams40 a 1′-40 a 5′, and the foil sets (not shown). The actuating mechanism45(5)′ comprises at least two pinion gears 142′ pivotally mounted withinthe intermediate foil support beams 40 a 2′-40 a 4′. The ends of therack gears 144′ that engage the pinion gears 142′ are rigidly attachedto the opposing surfaces of the adjacent support beams, for example, asshown with regard to the attachment of the rack gear 144′ to surface148′ of the foil beam 40 a 1 ′ and the opposing surface 149′ of the foilbeam 40 a 2′. This design insures that the spacing between the foilsupport beams 40 a 1′-40 a 5′ remains substantially equidistantthroughout the range of motion. The actuating mechanism 45(6)′ can beutilized in place of the pantograph mechanism 88′ described andillustrated with reference to FIG. 9B.

[0059] In the use of the actuating mechanism 45(5)′, the positions ofthe intermediate foil beams 40 a 2′-40 a 4′ and the trailing foil beam40 a 5′ can be adjusted by the use of at least two linear actuating(lead) screw assemblies (72′) (not shown) similar to that depicted anddescribed with reference to FIGS. 7 and 8A, that are connected inparallel to the foil beams and by a common actuator (73′) comprising adrive shaft (not shown). As the actuating screw assemblies (72′) movethe trailing foil beam 40 a 5′, the rack and pinion gear assemblymechanism 45(5)′ draws the intermediate foil beams 40 a 2′-40 a 4′,which are moved proportionally with the trailing foil beam 40 a 5′. Theindividual foil beams 40 a 1′-40 a 5′ are preferably supported by atleast two linear bearings (e.g., linear pillow blocks), for example, asshown and described with reference to FIGS. 6 and 8A (68′), that aresupported by shafts (70′) oriented perpendicular to the foil supportbeams 40 a 1′-40 a 5′ to insure the lateral alignment of the beams inthe machine and to control lateral and vertical movement.

[0060] The aforementioned mechanisms and methods can be utilized in anycombination to construct variable frequency “boxes”, foil sets and/orentire variable frequency gravity tables. The variable frequency box ofthe invention has numerous applications where paper machines arescheduled to run a variety of papers at varying speeds and stockconsistencies. Examples include, but are not limited to, fine papermanufacturers, publication papers, liner board, security papers, and thelike.

[0061] The mechanisms 45(1)′-45(5)′ of the invention described hereincan be readily combined with other known assemblies to alter the angleof each individual foil blade and/or raise or lower each foil blade intoand out of contact with the Fourdrinier wire.

[0062] The described foil beam assemblies operate in an environmentprone to contamination of the working parts. It is understood that theparts and mechanism described herein can be sealed or shielded duringoperation according to conventional methods to inhibit suchcontamination.

[0063] Referring now to FIG. 11, another embodiment of a variablefrequency (VF) assembly 37′ for dewatering in a papermaking apparatus isprovided in accordance with the invention. The dewatering assembly 37′comprises multiple elements (devices) that function in a dewateringcapacity. Such dewatering elements can include foil elements and tablerolls, for example.

[0064] In the illustrated embodiment, the assembly 37′ comprises twosets 36 a′, 36 b′ of dewatering elements 150 a′, 150 b′ supported on arail system 98′ affixed to a frame 100′ of a Fourdrinier table 10′(shown in phantom), as described with reference to the embodimentillustrated in FIGS. 9A-9B, although other arrangements and actuatorscan be utilized. In the illustrated example, the dewatering elements 150a′, 150 b′ are mounted on support beams mounted on rails 99 a′ of railsystem 98′, and attached to an actuating mechanism. The actuatingmechanism is operable to laterally move the dewatering elements 150 a′,150 b′ to space the elements apart by a standard interval, and tolaterally move at least one of the sets 36 a′, 36 b′ to space apart thesets by an integer multiple of the standard interval.

[0065] In the present embodiment, the sets 36 a′, 36 b′ includedewatering elements in the form of one or more foil beams 150 a′ and oneor more table rolls 150 b′. An example of a table roll 150 b′ isillustrated in FIGS. 12-15. Referring to FIG. 12, a table roll 150 b′ isgenerally composed of a rubber cover cylinder 154′ with stub ends 166′extending a significant distance from the cylinder ends to be supportedby a radial bearings 152′ in end bracket 170′ permitting rotation of thecylinder. The base 162′ serves as a support mechanism for the endbrackets 170′ and creates a scraper for water preventing itsreintroduction in to the web. The diameter of cylinder 154′ is generallyabout 2-3 inches.

[0066] The table roll 150 b′, like the foil beams 150 a′, is structuredto be slidably mounted on a support beam. A typical support beam is inthe form of a T-bar mount, although other configurations such as adovetail mount, and the like, can also be utilized. As shown, the tableroll 150 b′ includes a base 162′ with a mating slot 162′, shown as aT-shaped slot, running the full length of the base in the lower portionthat is adapted for slidably mounting lengthwise onto the support beammount. In the illustrated example, the table roll 150 b′ includes anextension member 166′ such as a rotatable shaft or rod that is mountedthrough an opening 168′ in an endplate 170′ attached to the base 162′.The endplate 170′ and base 162′ are preferably fabricated from bronze,stainless steel or fiber reinforced plastic.

[0067] The inclusion of a table roll 150 b′ as a dewatering element incombination with foil elements (beams) 150 a′ in the VF assembly 37′ isdesirable to achieve the desired stock action in those circumstances inwhich a slower moving papermaking machine is used, for example. Anotheradvantage is using foil beams and table roll(s) in combination is thatat slower speeds, table rolls introduce energy into the stock.

[0068] Referring now to FIGS. 16-17, in another embodiment of a variablefrequency (VF) foil assembly according to the invention, foil elements174′ that have a multi-surface foil blade are utilized in the assembly.Foil elements, as illustrated in FIG. 9A, for example, typically have afront edge, a flat leading surface for bearing the wire, and a trailingsurface angled at between 0° and 5° for draining water from the wire.The front edge meets the wire with an acute angle which sheers off waterhanging under the wire. Typically, the minimum distance X that can beachieved by moving the individual foil beams within a set is an about 2½inch pitch. However, there are applications for which a lower pitch isdesirable.

[0069] In the present embodiment, the assembly incorporates one or moredrainage foils 174′ that have two wire-contacting surfaces spaced afixed distance apart with a suction-forming section and a drainagesection therebetween. An example of a multi-surfaced drainage foil isdescribed for example, in U.S. Pat. No. 4,123,322 (Hoult), thedisclosure of which is incorporated by reference herein. In use, the toppart of the foil 174′ is positioned adjacent to a forming wire 14′.Referring to FIGS. 16-17, the foil 174′ is a unitary structure thatincludes a suction-forming section 176′ with a leading edge 178′, a wirecontacting surface 180′ and a trailing suction-producing surface 182′,and a trailing section with a leading edge 186′ and a wire contactingsurface 188′. A water drainage slot 190′ is located between thesuction-producing surface 182′ and the leading edge 186′ of the trailingsection 184′. The slot 190′ communicates with an array of holes 192′through which water drawn from the wire can be drained away. A web(s) orother support 194′ connects the suction-forming section to the trailingsection. The multi-surfaced foil element includes a mating slot 164′,shown as T-shaped slot, running the full length of the foil in the lowerportion, which cooperates with a mount on a support beam for sliding thefoil lengthwise onto the support beam.

[0070] According to the invention, the leading edge 186′ of the trailingsection 184′ of the foil element 174′ is positioned at a distance X fromthe leading edge 178′ of the suction-forming section 176′. Referring toFIG. 18, the multi-sectioned foils 174′ are placed in relation to eachother such that the spacing A-A between the leading edges 178′ and 186′of the multi-edged foil and the spacing B-B between the leading edge178′ of the leading foil 174 a′ and the leading edge 186′ of thetrailing foil 174 b′ are about equal. The construction of themulti-surface foil element 174′ is particularly useful in applicationswhere a low pitch is desired, for example, a 2-inch pitch or lower suchas a 1½ inch pitch.

[0071] In use in a variable frequency (VF) assembly according to theinvention, for example, the assemblies shown in FIGS. 9A and 11, thetwo-surface foil element 174′ can be slidably mounted onto a supportbeam 40′ affixed onto a rail system 98′ or other support, as describedhereinabove, to provide two or more sets of foils. As described above,an actuator attached to each of the foil elements and to the foil sets,operates to laterally move the foil elements such that the contactingsurfaces 180′, 188′ of the foil elements within a set are spaced apartby a standard interval X, and to laterally move at least one of the setsto space apart the sets by an integer multiple of the standard intervalX, preferably so that the combined frequency of the foil sets ismaintained at about 50 to about 90 hertz. With a multi-surfaced foilelement 174′ having an about 1½ inch pitch between contacting surfaces180′, 188, adjacent support beams 40′ are typically spaced apart atabout 3-inch intervals.

[0072] Also useful according to the invention, is a VF assembly thatincorporates one or more foil elements that are structured as anadjustable angle foil blade. The use of an adjustable angle foil allowsthe angle of the foil to be adjusted without removing the foil apparatusfrom the machine or stopping the machine. For example, FIG. 19illustrates a prior art adjustable angle foil 196′ described in U.S.Pat. No. 6,444,094 by Rulis (Wilbanks International, Inc.), thedisclosure of which is incorporated by reference herein, in which theangle of the foil is adjusted by rocking or tipping the entire foilblade. The variable pulse turbulation blade 196′ is mounted on a supportbase member 198′, and includes a flat leading surface 200′ adjacent theleading edge with an in-going angle (β) that is adjusted by acam-operated adjustment mechanism (not shown) while maintaining theheight of the blade relative to the conveyor 202′ substantiallyconstant. The foil angle (α) of the blade between its flat rear surface204′ and the conveyer 202′, is also adjusted when the in-going angle (β)is adjusted.

[0073] Other examples of adjustable angle foils are described in U.S.Pat. No. 5,169,500 by Mejdell, and U.S. Pat. No. 6,274,002 by Rulis(both to Wilbanks International, Inc.), and U.S. Pat. No. 5,486,270 toSchiel (J.M. Voith GmbH, Heidenheim, Germany), the disclosures of whichare incorporated by reference herein. Adjustable angle foils are alsocommercially available, for example, from IBS Paper Performance Group(Chesapeake, Va.), and CoorsTek (Hillsboro, Oreg.).

[0074] In use of the adjustable angle foil element 196′, the foilelement can be mounted on a beam support and onto a rail support toprovide two or more foil sets, similar to the illustration in FIG. 9A,for example. An actuator attached to each of the foil elements and tothe foil sets operates to laterally move the foil elements such that thecontact surfaces of adjacent foil elements are distanced at a standardinterval X and the foil sets are distanced at an integer multiple of X,in accordance with the invention.

[0075] The invention has been described by reference to detailedexamples and methodologies. These examples are not meant to limit thescope of the invention. It should be understood that variations andmodifications may be made while remaining within the spirit and scope ofthe invention, and the invention is not to be construed as limited tothe specific embodiments shown in the drawings. The disclosures of thecited references throughout the application are incorporated byreference herein.

What is claimed is:
 1. An assembly for dewatering in a papermakingapparatus, comprising: first and second sets of dewatering elements, thedewatering elements of at least one set comprising at least one foilbeam and at least one table roll; and an actuating mechanism operable tolaterally move and space apart the dewatering elements by a standardinterval, and to laterally move at least one of the sets to space apartthe sets by an integer multiple of the standard interval.
 2. Theassembly according to claim 1, wherein the dewatering elements aremounted in a support comprising a box shaped frame.
 3. The assemblyaccording to claim 1, wherein the dewatering elements are mounted on asupport structure comprising rails.
 4. An assembly for a papermakingapparatus, comprising: two or more sets of dewatering elements, thedewatering elements of at least one set comprising at least one foilbeam at least and one table roll; and an actuating mechanism operable tolaterally move the dewatering elements relative to each other to providea pitch distance X between each dewatering element, and to provide adistance that is an integer multiple of the pitch distance X between adewatering element of a first set and an adjacent dewatering element ofa second set.
 5. An assembly for a papermaking apparatus, comprising: atleast first and second sets of dewatering elements, each set comprisingat least two dewatering elements mounted on a support, and an actuatingmechanism connecting the at least two dewatering elements and the setsof dewatering elements, the actuating mechanism operable to alter pitchdistance between the dewatering elements whereby the dewatering elementsare substantially equidistant relative to each other, and the sets ofdewatering elements are spaced apart at an integer multiple of thedistance between the dewatering elements.
 6. The assembly of claim 5,wherein the dewatering elements of the first set comprises at least onefoil beam and at least one table roll.
 7. An assembly for a papermakingapparatus, comprising: at least first and second sets of dewateringelements, each set comprising at least a first and second dewateringelement mounted on a support, and an actuating mechanism connecting thedewatering elements and the sets of dewatering elements, the actuatingmechanism operable to laterally move and space apart the dewateringelements by a standard interval, and to laterally move at least one ofthe sets of dewatering elements to space apart the sets by an integermultiple of the standard interval.
 8. The dewatering assembly of claim7, wherein the first set of dewatering elements comprises one or morefoil beams and one or more table rolls.
 9. The assembly according toclaim 7, wherein each of the sets comprises a leading and a trailingdewatering element; and the actuating mechanism is connected to theleading dewatering elements of the first and second sets, and isoperable to move the leading dewatering element of the second setrelative to the trailing dewatering element of the first set to alter adistance between the sets.
 10. The assembly according to claim 7,wherein each of the sets comprises a leading and a trailing dewateringelement; and an actuator operable to laterally move the trailingdewatering element relative to the leading dewatering element.
 11. Theassembly according to claim 7, wherein the dewatering elements aremounted on a support comprising rails.
 12. The assembly according toclaim 11, wherein the support comprises an inner pair of rails and anouter pair of rails, and the first dewatering element is mounted on oneof the pair of rails and the second dewatering element is mounted on theother of the pair of rails.
 13. The assembly according to claim 12,wherein the first dewatering element of the first set is affixed to therails in a stationary position, and the first dewatering element of thesecond set and the second dewatering elements of the first and secondsets are slidably mounted on the rails.
 14. The assembly according toclaim 7, wherein the actuating mechanism comprises: a mating screw andnut assembly in rotatable contact with a gear mounted on a shaft, androtating the shaft causes said lateral movement of the dewateringelements, the sets, or both.
 15. The assembly according to claim 7,wherein the actuating mechanism comprises a hydraulic or pneumaticdevice.
 16. The assembly according to claim 7, further comprising atleast one linear bearing supported by a shaft, the linear bearingattached to at least one dewatering element and oriented perpendicularto the dewatering elements to maintain lateral alignment of thedewatering elements relative to each other.
 17. The assembly accordingto claim 7, wherein the actuating mechanism comprises a hydraulic orpneumatic cylinder attached on at least one of the dewatering elementsand comprising a mechanism for communicating the position of theattached element to a controller and receiving a signal from thecontroller to actuate the cylinder to laterally move the attachedelement to alter the pitch distance between the attached element andanother element.
 18. The assembly according to claim 7, wherein theactuating mechanism comprises a first actuating screw and nut assemblyaffixed to one of the dewatering elements and oriented perpendicular tothe dewatering elements, the actuating screw connected to an actuatingdevice operable to move the actuating screw to laterally move theaffixed element to alter the pitch distance between the affixed elementand another element.
 19. The assembly according to claim 18, wherein theactuating device comprises a worm/gear assembly mounted on a driveshaft.
 20. The assembly according to claim 7, wherein the actuatingmechanism comprises a pantograph assembly connecting the dewateringelements.
 21. The assembly according to claim 7, wherein the actuatingmechanism comprises a telescoping shaft assembly.
 22. The assemblyaccording to claim 7, wherein the actuating mechanism comprises a rackgear engaged with a pinion gear.
 23. An assembly for a papermakingapparatus, comprising: first and second sets of dewatering elements,each set comprising at least two dewatering elements supported on a railsystem, the dewatering elements of at least one set comprising at leastone foil beam and at least one table roll; and a mechanism operable tomove at least one dewatering element of the first set to alter a pitchdistance between two dewatering elements of the first set by a distanceX, and to move a dewatering element of the second set relative to thefirst set to alter an interset distance between the first and secondsets by an integer multiple of distance X.
 24. The assembly according toclaim 23, wherein the rail system is affixed to a frame of a papermaking machine.
 25. The assembly according to claim 23, wherein themechanism is operable to move a dewatering element of the second set bya distance X from a second dewatering element of the second set.
 26. Inan apparatus comprising a two or more sets of dewatering elements, eachset comprising a plurality of dewatering elements mounted on a support,a mechanism to alter the pitch distance between individual dewateringelements of the sets whereby the individual dewatering elements aremaintained at a distance X relative to each other, and to alter thedistance between adjacent sets to maintain the distance as an integermultiple of the distance X of the dewatering elements.
 27. In adewatering assembly comprising a two or more sets of dewatering elementswith each set comprising a plurality of dewatering elements each beingmounted on a support, a mechanism for adjusting the frequency of theassembly, the mechanism connected to the dewatering elements andoperating to alter pitch distance between individual dewatering elementsof the set to maintain the elements substantially equally spacedrelative to each other, and connected to the sets and operating to alterthe distance between the sets to an interset distance as an integermultiple of the spacing.
 28. A foil beam assembly, comprising: at leasta first and a second foil beam set, each foil beam set comprising aplurality of foil beams; and an actuating mechanism operable tolaterally move the foil beams to space apart the foil beams by astandard interval, and to laterally move at least one of the foil beamsets to space apart the foil beam sets by an integer multiple of thestandard interval.
 29. The foil beam assembly according to claim 28,wherein the foil beam sets have a combined frequency adjustable by thelateral movement of the foil beams by the actuating mechanism.
 30. Thefoil beam assembly according to claim 28, wherein the foil beam setshave a combined frequency adjustable by the lateral movement of the atleast one foil beam set by the actuating mechanism.
 31. The foil beamassembly according to claim 28, wherein at least one of the foil beamsets comprises at least one table roll, and the actuating mechanism isoperable to space apart the table roll relative to a foil beam by astandard interval.
 32. A foil assembly, comprising: at least a first anda second foil set, each foil set comprising a plurality of foilelements; and an actuating mechanism operable to laterally move the foilelements to space apart the foil elements by a standard interval, and tolaterally move at least one of the foil elements sets to space apart thefoil sets by an integer multiple of the standard interval.
 33. The foilassembly of claim 32, wherein the foil elements comprise at least onefoil element comprising a unitary structure comprising twowire-contacting surfaces spaced apart by the standard interval with asuction-forming section and a drainage section therebetween.
 34. Thefoil assembly of claim 32, wherein the foil elements comprise at leastone foil element comprising a unitary structure comprising: asuction-forming section comprising a leading edge, a wire contactingsurface, and a suction-producing surface; a trailing section comprisinga leading edge and a wire contacting surface; and a water drainage slotdisposed between the suction-producing surface and the leading edge ofthe trailing section.
 35. A foil assembly, comprising: at least a firstand a second foil set, each foil set comprising a plurality of foilelements, at least one foil element comprising a unitary structurecomprising two wire-contacting surfaces spaced apart by a standardinterval with a drainage section therebetween; and an actuatingmechanism operable to laterally move the foil elements to space apartthe foil elements by the standard interval, and to laterally move atleast one of the foil elements sets to space apart the foil sets by aninteger multiple of the standard interval.
 36. The foil assembly ofclaim 35, wherein the at least one foil element comprises: asuction-forming section comprising a leading edge, a wire contactingsurface, and a suction-producing surface; and a trailing sectioncomprising a leading edge and a wire contacting surface.
 37. The foilassembly of claim 35, wherein the drainage section comprises a drainageslot disposed between the suction-producing surface of thesuction-forming section and the leading edge of the trailing section.38. An assembly for dewatering in a papermaking apparatus, comprising:at least a first and a second set of dewatering elements, each setcomprising at least one foil element comprising a unitary structurecomprising two wire-contacting surfaces spaced apart by a standardinterval with a drainage section therebetween; and an actuatingmechanism operable to laterally move the dewatering elements to spaceapart the dewatering elements by the standard interval, and to laterallymove at least one of the dewatering elements sets to space apart thesets by an integer multiple of the standard interval.
 39. The assemblyof claim 38, wherein the at least one foil element comprises: asuction-forming section comprising a leading edge, a wire contactingsurface, and a suction-producing surface; and a trailing sectioncomprising a leading edge and a wire contacting surface; and thedrainage section comprises a drainage slot disposed between thesuction-producing surface of the suction-forming section and the leadingedge of the trailing section.
 40. The assembly of claim 38, wherein atleast one set comprises one or more table rolls.
 41. The assembly ofclaim 38, wherein at least one set comprises a foil beam having a singlewire contacting surface.
 42. An assembly for dewatering in a papermakingapparatus, comprising: at least first and second sets of dewateringelements, at least one set comprising at least one adjustable anglefoil; and an actuating mechanism operable to laterally move thedewatering elements to space apart the dewatering elements by thestandard interval, and to laterally move at least one of the dewateringelements sets to space apart the sets by an integer multiple of thestandard interval.
 43. A method of varying the frequency of a set ofdewatering elements, comprising the steps of: providing at least a firstand second set of dewatering elements, each set comprising two or moredewatering elements mounted on a support structure, and an actuatingmechanism interconnecting the dewatering elements and the sets, theactuating mechanism structured to laterally move the dewatering elementsrelative to each other and to laterally move the sets relative to eachother; and actuating the actuating mechanism to laterally move thedewatering elements relative to each other to distance X and foil beamsto alter the distance there between and maintain the foil beams at adistance X and to laterally move the sets relative to each other to adistance as an integer multiple of the distance X.